Mevinolin, the starting material for the novel process of this invention is a fermentation product described in U.S. Pat. No. 4,231,938.
Hydrogenation products, including tetrahydromevinolin are described in U.S. Pat. No. 4,351,844.
Compound I and processes for its preparation are disclosed in published European application EP No. 0033538. However, the processes disclosed involve five distinct chemical steps from mevinolin involving (1) reduction; (2) de-esterification of the 8-ester group; (3) protection of the 4-hydroxy of the pyranone group; (4) re-esterification with the desired 2,2-dimethylbutyryl; and (5) deprotection of the 4-hydroxy, not necessarily in that order.
Now, with the present invention there are provided novel processes for the preparation of Compound I involving only two chemical steps resulting in overall yields much higher than those realized by the prior art, with the expenditure of much less time, labor and materials.